Dwarfs

Dwarfs! Short, stout, but hardy and excellent at smithery (envy
them, most of us don't have a hauberk to throw on now
and then).

By the Narnia.com armor pictures and the size
comparison charts, it appears that Black Dwarfs are in the witch's
service, whereas Red Dwarfs are on Aslan's side. The sides, in the
book, are distinguished by hair and beard color: black dwarfs have
black beards, hard like horse hair, and red dwarfs have soft red hair
like foxes.

Black
Dwarfs

The costume appears to start with a long sleeved tan or gray tunic,
with sleeves gathered in at the cuff, the fabric of a heavy material
with thin vertical stripes.

Over that is a mail shirt, short sleeved, with a
wide collar that drapes about the neck. This was originally thought to
be a coif, but it appears to be simply a large collar. The back,
however, form a coif when wanted.

A dwarf has one leather belt. Off that belt comes
his sheath, hanging by a leather at the side and the back, and another
leather that goes over his right shoulder to hold his quiver.

The video game image appears to be quite
accurate, therefore, we'd trust it more than the action figure on extra
details. It shows brown trousers, a long-sleeved tan tunic, tall black
boots, his helmet, as well as the hauberk, sword, and quiver.

Quiver
Starting from the base, the quiver is shaped like a long rectangle, and
has a strip of leather tooling straight down the wide side: a design of
geometric arrow/triangle shapes.

A metal band runs about the opening, and another
one 1/3 of the way down the quiver. A metal tip bossed at the end of
the quiver forms a point, with a design inset.

About two inches above the end is a strip of
leather set down with rivets, fastened all the way around, and taking
up about 1/3 of the quiver. Another design, more intricate, is bossed
onto that. The use of this section is unknown, except that it holds the
quiver to the belt.

The last decoration, at the top, is a metal band
that serpentines down the quiver and around, beginning at just above
the leather accessory to below the quiver rim.

Helmet
The helmet is round, with 18-20 ridges. If you can excuse the
comparison, it nearly resembles the underside of a Bundt cake pan. The
top comes to a point with a knob on the end, and two strips of metal
are twisted together around the helmet to form the lower rim.

Beneath the helmet is worn leather cap, with a
collar off the back to protect the neck, and two "wings" in front of
the ears.

Ginarrbrik

Ginarrbrik has a red coat, lined in a dirty white
fur. The cuffs of the long sleeves are gold fabric, embroidered in a
gold thread in two designs. This is seen at the hem of the coat as well.

We can't see what he wears under his coat, but the
video game and action figure images suggest a long sleeved red shirt,
(the video game headshot suggests velvet with gold acid etchings). The
action figure image shows a thick band of gold design on the cuffs.

Ginarrbrik wears high laced boots, with curled,
pointed toes.

He either dons a separate white fur vest at the
battle - the action figure shown is a battle figure - or this is an
action figure inaccuracy. He carries his sword and a staff.

His red cap has two long wings in front of the
ears, and a long "tail" down the back. His beard roots are white, and
brownish red further down - turning old! His fingers are heavily
jeweled: several rings decorate his fingers.

In a chat with Kiran Shah
(Ginarrbrik) on TheOneRing.net,
he says... not much about his costume! But he does mention that he has
"a long beard that goes all the way to the floor." See the transcript
at the above link.